Acne

Sebaceous glands are attached to hair follicles and are found mostly on the face, neck back and chest. These glands produce an oily substance called sebum. Sebum can clog the hair follicles and lead to whiteheads and blackheads.
Hormonal changes during menstrual cycles, menopause and pregnancy affect the emergence of acne in women. Studies have shown that acne occurs more frequently during the week before menstruation.
Acne can occasionally cause by, or aggravated by, medication such as oral steroids, contraceptive agents in females, testosterone, and anabolic steroids. During pregnancy, acne can both clear and get worse.
Acne is generally more sever and tends to occur more frequently in men than women, because men produce more androgen, the hormone that stimulates sebaceous gland activity.
Many cosmetics are comedogenic and therefore create whiteheads and blackheads acne. The use of water based cosmetics is much more preferable than the use of oil based cosmetics. Oil based is hard to remove and caused more clogged pores.